"Just how red-hot is the current worldwide expansion? 'This is far and away the strongest global economy I've seen in my business lifetime,' U.S. Treasury Secretary Hank Paulson declared on a recent visit to FORTUNE's offices. That may come as news to many Americans, whose boom-time memories are stuck in the 1990s, when Silicon Valley was the epicenter of our growth fantasies…

"John Chambers, who last fall opened Cisco's new Globalization Center in Bangalore, seconds the notion that 'this is the strongest global trend' of his career. 'There is a unique balance today,' he says. 'More than half of GDP growth is coming from emerging countries. And yet the developed countries are also doing pretty well. It is something we have never seen before…'

"The last global good time in the 1970s, of course, ended in a nasty bout of double-digit inflation, spawning the worst stock market crash since the Great Depression, plus other horrors, such as the rise of disco. Is that sorry past our future? Not necessarily. But with nervousness rising over everything from Bear Stearns' battered hedge funds to tightening lending standards that could clog the crowded private-equity deal pipeline, let us first explain how one can be, as we are, short-term bearish but long-run bullish on the global growth story.

"When it comes to markets, we hold these truths to be self-evident: (1) It's never different this time, and (2) Every boom leads to financial excesses that spark its undoing. (That's why they're called business cycles.) 'The necessary conditions for a bubble to form are quite simple and number only two,' investor Jeremy Grantham noted in a recent newsletter headlined 'The First Truly Global Bubble.' 'First, the fundamental economic conditions must look at least excellent--and near perfect is better. Second, liquidity must be generous in quantity and price: It must be easy and cheap to leverage.' That pretty much sums up the world we've been living in, a world where prices skyrocketed for Miami condos, Indian stocks, and office towers in Dubai."

(“The Greatest Economic Boom Ever.” Rik Kirkland. Fortune: July 23, 2007. Vol.156, Iss. 2; pg. 120)YIN AND YANG show us that the seeds of every opposite are found in the heart and strength of every trend. When everyone knows something, nobody knows anything. Head for the hills when "The old rules no longer apply," or "Things are completely different this time." ouch!